RHEEM Classic 90 Plus Condensate Issue

Here on my service bench I have a RHEEM Classic 90 plus gas furnace. This unit was removed from a existing home because it was oversized for the home and it was having serious service issues. The owner felt it was about time to upgrade to a 95% American Standard instead of putting money into this furnace. Like all brands of furnaces RHEEM has had its fair share of issues. I will talk about the condensate drip issue.

RHEEM Classic 90 plus

RHEEM Classic 90 plus

The only thing I like about RHEEM furnaces is they have elected to keep the spark ignition, not using the HSI that every other manufacture has turned to. I truly do not understand the industries thinking about HSI versus spark.

Lower section of the RHEEM classic 90

Lower section of the RHEEM classic 90

Above you see the lower section of the RHEEM classic 90 plus, its this area that has major service issues that burden the owners of this particular model. If you own this model you will have to keep up on the maintenance, especially at the burners.

Inducer Burner Section.

Inducer Burner Section.

1) With the RHEEM Classic 90 Plus downflow there is and/or will be a leak developing at the connection point of the inducer and exhaust pipe. This leak is located exactly over the ignitor and the primary & secondary burners.

Ignitor Burner Section

Ignitor Burner Section

2) The leak will start soon after the furnace starts burning and will continue during the run cycle and eventually stop after the unit stops and all the moisture is deplenished. The heat from the burners drys up the moisture causing scaling in and on the burners and ignitor. Most of the scaling on this unit was removed from the burner and ignitor area in an effort to get the unit running until it could be replaced, but you can still see the area of concern.

Ignitor Burner Removed

Ignitor Burner Removed

Above is the Ignitor and 2 burners removed to show how much scaling and corrosion can occur, you will usually find just as much or more on the burners above.

Flame Sensor

Flame Sensor

3) On the far left of the burners is the flame sensor, once the main burner on the far right is lit, it in return will light the next burner (like domino’s) until the far left burner is lit. The flame sensor reports back that we have ignition and the furnace can move on to the fan sequence. IF your first or second burner has be compromised with scale or corrosion this domino effect will not occur in a timely fashion or even at all. The flame sensor will not detect flame and the unit will shut down. The unit will try several times over and over until it gets igniton or until it locks out. During this time you will notice erratic burner behavior and possibly a strong smell of gas.

Keep in mind I was called out on a sales call to replace this furnace, the previous technician was out there 3 weeks prior and did a full maintenance. I found 2 burners clogged and a the ignitor corroded. Its obvious some heating technicians are not aware or simply overlook this issue, if you have this model make sure you get your burners cleaned.

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